Acta Herpetologica 14(2): 71-80, 2019 DOI: 10.13128/a_h-7744 Podarcis siculus latastei (Bedriaga, 1879) of the Western Pontine Islands (Italy) raised to the species rank, and a brief taxonomic overview of Podarcis lizards Gabriele Senczuk1,2,*, Riccardo Castiglia2, Wolfgang Böhme3, Claudia Corti1 1 Museo di Storia Naturale dell’Università di Firenze, Sede “La Specola”, Via Romana 17, 50125 Firenze, Italy. *Corresponding author. E-mail: [email protected] 2 Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università di Roma La Sapienza, via A. Borelli 50, 00161 Roma, Italy 3 Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, D53113, Bonn, Germany Submitted on: 2019, 12th March; revised on: 2019, 29th August; accepted on: 2019, 20th September Editor: Aaron M. Bauer Abstract. In recent years, great attention has been paid to many Podarcis species for which the observed intra-specific variability often revealed species complexes still characterized by an unresolved relationship. When compared to oth- er species, P. siculus underwent fewer revisions and the number of species hidden within this taxon may have been, therefore, underestimated. However, recent studies based on genetic and morphological data highlighted a marked differentiation of the populations inhabiting the Western Pontine Archipelago. In the present work we used published genetic data (three mitochondrial and three nuclear gene fragments) from 25 Podarcis species to provide a multilocus phylogeny of the genus in order to understand the degree of differentiation of the Western Pontine populations. In addition, we analyzed new morphometric traits (scale counts) of 151 specimens from the main islands of the Pontine Archipelago. The phylogenetic analysis revealed five principal Podarcis groups with biogeographic consistency. The genetic distinctiveness of the Podarcis populations of the Western Pontine Islands is similar or even more ancient than those observed in numerous other pairs of Podarcis sister species. In the light of these evidences we raise the Western Pontine lizards to specific rank; thus they should be referred to as Podarcis latastei. Keywords. Reptilia, Podarcis latastei, Podarcis siculus, insular lizards, Mediterranean. INTRODUCTION ing, as some predecessors did, only “varieties“ within this species (Boulenger, 1887, 1905, 1913, 1920). His main The wall lizards belonging to the genus Podarcis antagonist, representing the taxonomic “splitter“ fac- Wagler, 1830 are among the most speciose vertebrates in tion, was Ludwig von Méhely (1862-1953) who consid- Europe, representing one of the most important faunis- ered many of Boulenger’s “varieties” to be distinct species tic elements of the Mediterranean insular biota. Origi- (Méhely, 1907, 1909). He wrote: «Like a night-mare, the nally, two opposite taxonomic viewpoints (“lumping“ and so-called muralis question is burdening the mind of her- “splitting“) were – partly emotionally – discussed in the petologists» (Méhely, 1907). Despite modern approaches, late 19th and early 20th centuries. At that time the most molecular genetics included, Méhely was closer to the prominent representative of the “lumpers“ was George A. current concept than his more influential contempo- Boulenger (1859-1937) who joined numerous wall lizards rary colleague; however, the number of Podarcis species together under the name “Lacerta muralis“ distinguish- is still debated. For example, 21 taxa were recognized as ISSN 1827-9635 (print) © Firenze University Press ISSN 1827-9643 (online) www.fupress.com/ah 72 Gabriele Senczuk et alii valid species by Speybroeck et al. (2010), whereas other ventotenensis = Podarcis siculus ventotenensis (Taddei, authors have suggested 23 (Sindaco et al., 2013; Uetz and 1949) from Ventotene; Lacerta sicula pasquinii = Podar- Hošek, 2016; but see Psonis et al., 2017). The taxonomic cis siculus pasquinii (Lanza, 1952) from Scoglio Cappello wavering of the genus Podarcis is mainly due to the pres- near Palmarola; Lacerta sicula patrizii = Podarcis siculus ence of marked intra-specific variability with multiple patrizii (Lanza, 1952) from Zannone; Lacerta sicula lan- species complexes characterized by unresolved relation- zai = Podarcis siculus lanzai (Mertens, 1967) from Gavi ships (Harris and Arnold, 1999; Oliverio et al., 2000; and Lacerta sicula palmarolae = Podarcis siculus pal- Harris et al., 2005; Lymberakis et al., 2008). Table 1 sum- marolae (Mertens, 1967) from Palmarola (cfr. Lanza and marizes this taxonomic/nomenclatural history of the cur- Corti, 1996; Corti et al., 2010). rently recognized Podarcis species. Podarcis siculus parkeri was synonymized with P. s. In contrast to the great taxonomic attention paid sanctistephani (Mertens and Wermuth, 1960; Mertens, to numerous Podarcis species, P. siculus has undergone 1965), which is believed to have become extinct during fewer revisions and the number of species hidden within the first decades of the last century (1914 at the latest), this taxon may have been underestimated. Podarcis sicu- and replaced by P. s. siculus (Mertens, 1965). Henle and lus (Rafinesque-Schmaltz, 1810) was originally described Klaver (1986), reviewing the intraspecific taxa, followed as Lacerta sicula. However, because of its distribution Mertens (1965) in considering P. s. ventotenensis as a syn- over a large part of Italy (Sicily, Sardinia and numerous onym of the nominotypical form, and listed P. s. latastei, minor islands, islets and rocks) and Dalmatia, several P. s. lanzai, P. s. pasquinii, P. s. patrizii and P. s. pal- subspecies were described. Some of them were originally marolae as valid subspecies. These five taxa occur in the assigned to “Lacerta” muralis (more than 90 were listed Western Pontine Islands, which are believed to have been together with their type localities by Henle and Klaver, connected to the mainland in the Pleistocene, whereas 1986). This situation led some authors to hypothesize the the Eastern Pontine Islands (Ventotene, Santo Stefano) presence of a species complex similar to those observed seem never to have been, being located along the 500 m in other Podarcis assemblages (Oliverio et al., 1998, 2000; isobath (Woldstedt, 1958; Mertens, 1965, 1967). Harris and Sa-Sousa, 2002). More recent studies based on The deep genetic distance recently found between mitochondrial (Podnar et al., 2005) and nuclear (Senc- the Eastern and the Western Pontine Islands populations zuk et al., 2017) markers have supported the monophyly (Senczuk et al., 2018a), geometric morphometrics (Senc- of P. siculus and revealed surprisingly high genetic diver- zuk et al., 2018b), classical morphometric and meristic gences between the main constituent evolutionary line- data, as well as an updated time calibrated multilocus ages, most comparable to those observed between many phylogeny of Podarcis (Wagler, 1830), all suggest that the recognized Podarcis species (Harris et al., 2005). In addi- Western Pontine lizards deserve their own specific status tion, recent studies using molecular markers (mitochon- and should be referred to as Podarcis latastei (Bedriaga, drial and nuclear DNA) and geometric morphometrics 1879), which we characterize and redescribe here. have revealed that the populations from the Western Pontine Islands represent an evolutionarily independent unit (Senczuk et al., 2018a, 2018b). The genetic distances MATERIALS AND METHODS of these populations with respect to mainland ones were extraordinary high (p-distances of 7-10% for the mtDNA Molecular phylogenetics cytb gene), and the head morphology was clearly distin- guishable with respect to the mainland and Sicilian popu- To obtain a robust and time calibrated phylogeny of Podar- cis as a whole, three mitochondrial (16s; cytb, and nd4) and lations (Senczuk et al., 2018a; 2018b). three nuclear (mc1r, pod15b and pod55) gene fragments from The Pontine Archipelago is located 40 km off the 25 Podarcis species, including several subspecies, were retrieved Tyrrhenian coast and comprises the Western Pontine from GenBank (all samples are reported in Fig. 1 and Table islands Ponza, Palmarola, Zannone and Gavi, and the 1, localities and accession numbers are reported in Appendix Eastern Pontine islands Ventotene and Santo Stefano. 1, Table A1). Most of the retrieved sequences for each species From the Pontine Archipelago, the following nominal belong to the same individual, when not possible we selected insular intraspecific taxa have been described: Lacerta individuals of close geographic origin. All final consensus align- muralis var. latastei = Podarcis siculus latastei (Bedriaga, ments were computed for each gene separately using BioEdit 7.2 1879 a, b) from Ponza; Lacerta muralis parkeri = Podarcis (Hall, 1999). Coding gene fragments (cytb, nd4 and mc1r) were translated into amino acids to assess the lack of stop codons. siculus parkeri (Mertens, 1926) from Santo Stefano; Lac- For each alignment we used jModelTest v.2.1.3 (Darriba erta sicula sancti-stephani = Podarcis siculus sanctistepha- et al., 2012) to assess the best model of nucleotide evolution ni (Mertens, 1926) from Santo Stefano; Lacerta sicula under the corrected Akaike Information Criterion (AICc). To New Podarcis species from Western Pontine Islands 73 Fig. 1. Distribution of the genus Podarcis and location of the samples used for the phylogenetic analysis, as reported in Table 1. Geographic distribution of Podarcis latastei is also reported at the top right. reconstruct phylogenetic relationships we